There are ways to prevent them from selling to another buyer should they put the house on the market again in Feb.

What's preventing the seller and end buyer "hooking up" and meeting after the expiration date and cutting out the "wholesaler" me.

Thanks to anyone who takes the time to respond, this one has been (stupidly) causing me a mental roadblock and preventing me from taking action steps.

Your perspective might have just prevented me from making an expensive mistake. 

Perhaps a short purchase/sale contract would get things going and the contingencies will give me an exit if legalities will prevent it from closing? 

Yes, they can cost you 10% of the rent income but a good one will actually put more money in your pocket by protecting your asset, keeping you at market rate, preventing losses due to bad tenants, etc.

If the unit has been inspected, but not deleaded, you also cannot do any construction or remodeling in the unit, they consider that unauthorized deleading and it will prevent you from ever getting a lead cert.

A neighbor might want to make some money from putting an ADU on it, or at least preventing the lot from being developed in a way that person doesn't like.2.

   As a remodeling contractor I have seen homes with 10s of thousands of needed repair that could have been prevented with a bit of proper maintenance.

If the unit has been inspected, but not deleaded, you also cannot do any construction or remodeling in the unit, they consider that unauthorized deleading and it will prevent you from ever getting a lead cert.